Author Topic: T-Rex Fuel Tank Classic 12vAC - Adapter to drop to 9vAC for Whammy IV?  (Read 5373 times)


Hello all!

Sorry if this is the wrong forum. I'm trying to see if my Whammy IV can be powered off my Fuel Tank. I understand that the Whammy runs 9vAC and the Fuel Tank only has a 12vAC output.

Is it possible to drop the voltage down to 9vAC to enable me to run the Whammy? I doubt it would work well if it can, but I thought I would ask.



I think maybe we should get a new forum area: Fixing stompboxes. Putting questions like this in "building your own stompboxes" (which is where most of these kind of questions usually go) seems non-intuitive.

The digital & DSP forum is more about digital and DSP specific questions (involving programming, digital signal processing, digital circuitry, etc.). Your pedal IS digital but your specific question is analog. Just FYI, not meaning to be offensive, nobody really cares that you posted it here. But you'd probably get better answers in the BYOSB forum.

AC voltage is hard to adjust efficiently without transformers.

It's very likely that 12VAC wouldn't harm the Whammy at all. My guess is that the power section is just a diode bridge into one or more linear regulators. Although you can't count on this: maybe there's an unregulated DC line somewhere that won't like any boost. If you had the schematic it would be easy to check. Or if you are experienced enough to be able to see how they built the power section after opening it up.


I ruined someone's processor at a concert a few days ago by telling them a random 12v AC psu laying around wouldn't hurt the 9v AC input.  Now I have to see if I can fix it.


Yeah I was under the assumption that running 12vAC through it wouldn't be good for it.

I may just have to buy another power supply.